1.
Field of the Invention
This invention relates generally to hand-held cutting implements. Specifically, this invention relates to cutting implements used for making measured scoring lines or cuts in linear surfaces, such cutting implements being structured to facilitate unencumbered and accurate scoring or cutting.
2. State of the Art
Cutting implements generally comprising a hand-held housing with a shortened blade positioned at one end of the housing are well-known. See, for example, U.S. Pat. No. 1,843,535 to Arnold issued Feb. 2, 1932. Cutting implements of this type may be adapted for specialized use in scoring or cutting various surfaces, such as cardboard boxes. Such cutting implements are typically known in the art as utility knives and may include retractable means for securing the blade within the housing to prevent accidental encounter with the blade.
Another common use of utility knives is in handling and customizing building materials for construction purposes. Specifically, utility knives are frequently used to score, cut and trim sheets of drywall and the like for use in constructing walls and ceilings. When so used, as in other similar applications, a score line or cut must be made along a length of board at an equal distance from the raw edge of the board. Measuring means are used to calculate the desired distance to be cut from the edge of the board, then the blade of the knife is moved along the surface of the board along a demarcated or imagined line corresponding to the desired distance to be cut.
Most frequently, a tape measure is used to measure the distance for cutting or scoring. Those in the art, wishing to simplify or facilitate the measurement aspect of cutting with utility knives, have developed utility knives having measuring means associated therewith. See, for example, U.S. Pat. No. 2,952,025 to Johnson issued Sep. 13, 1960. Though providing a ready source for measuring, such utility knives have proven cumbersome and inaccurate.
Most often, a separate tape measure is used. The housing of the knife is held in the hand while the metal tab of the tape measure is held against the blade with the thumb. The housing of the tape measure is held in the other hand and the fingers are used to retain the tape measure at a point on the tape corresponding to the desired length to be cut. Beginning at the top of the board and with the blade of the knife poised over the surface, both hands are moved downwardly. The hand with the tape measure is kept close to the edge of the board while the hand holding the knife urges the blade into the surface and holds the tape taut against the blade.
Problems are frequently encountered in measuring and cutting in the manner previously described, including slippage of the blade and inaccurate cutting or scoring. Others in the art, having recognized these problems, have attempted to address some of them through modified designs. For example, U.S. Pat. No. 4,255,856 to Mackie, issued Mar. 17, 1981, describes a utility knife having a plate positionable against the blade of the knife, the plate having a slot therein for retaining the metal tab of a tape measure. U.S. Pat. No. 4,993,093 to Goldwitz, issued Feb. 19, 1991, provides a utility knife housing having a slot formed in the upper surface thereof to retain the metal tab of a tape measure.
The previously identified utility knives each have inherent problems which present dangerous conditions for cutting, or result in inaccurate cutting. Specifically, extra plates positioned near the blade result in interference between the cutting blade and the surface to be cut. Further, such blades do not provide ready use by both right-handed and left-handed or ambidextrous persons. Slots formed in the upper surface of the knife require awkward positioning of the thumb or digits to hold the tab of the tape measure in secure engagement with the slot and result in the tape measure being positioned with the numerals away from the user.
Thus, it would be an improvement in the art to provide cutting means for scoring and cutting surfaces which, when used in connection with measuring means, provide unencumbered and accurate cutting. Additionally, it would be an improvement in the art to provide measuring structure in combination with a utility knife which provides convenient and accurate measurement.
A further problem encountered by persons using utility knives in construction work is that the knife is used to trim the edges of drywall or the like to make a mitered edge having a forty-five degree angle. The mitered or beveled edges of two sheets are then joined together to form a corner, as in a room. Conventional utility knives provide no guideline for making a precise forty-five degree angle. Thus, construction workers must "eye" the edge of the sheet and estimate an approximate forty-five degree angle. Inaccurate angles lead either to repeated trimming until the correct angle is achieved or patching the corner once the two edges are joined to hide the improperly cut angle.
Thus, it would be an improvement in the art to provide a utility knife which is configured to provide guidance for making accurate forty-five degree trimming of edges to achieve precisely mitered corners in drywall construction or the like.